Machine tool



Jan. 15, 1957 H. NADERHOFF MACHINE TOOL Filed Feb. l2, 1952 QQQL .mllhbl(lvm United States Patent Gf 2,777,518` Y' MACHINE TOOL HeinrichNaderhoif, Goppingen, Wurttemberg, Germany, assignor to L. Schuler A.G., Goppingen, Wurttemherg, Germany Application February 12, 1952,Serial No..271,125 Claims priority, application Germany March 1, 1951Claims. (Cl. 164-50) ment, are also'started by hand, and iinallythe tooland the work feed are brought to rest after completed workk operations.

The present invention, however, consists in providing A an electricalcontrol system having a press button startblank, in the case of a groove'punching machine, a fast return travel of the guide frame for the workblank, and lautomatic switching olf means for the fast return travel ingswitch for switching on a power driven fast return f travelof the feedmeans after the insertion of a work when said feed means reaches its endposition, automatic f switching on means for the tool movement and meansdependent on said movement for the stepwise work feed at the end of awork operation. The great manual exertion required for the returnmovement of the feed means, in the case of groove punching machines, theholder frame, vand the manual starting, are all overcome by theelectrical control system'according to the present invention. The.starting now takes place without any physical strain by mere Iactuationof an electrical hand or pedal switch, whereupon the return travel ofthe feedl means to its initial position and its reversal take placeautomatically, Machines inv accordance with the invention are thereforemost suitable for loperation by younger and unskilled operators,particularly lesser physical strength.

young persons of According to another feature of the invention, the

power drive means for the fast return travel comprises an electricmotor, a -disc coupling actuated by an; electromagnet in rdependency onthe control system to engage and disengage `said motor, and means foroperating said electromagnet including a circuit breaker andyindependent switch-on and switch-off press-button switches. Theinvention also comprises the inclusion inthe sys- 20 moves in thedirection of the arrow 20.

phase vnetwork RST, through fuses 5, an electric motor 'i The pressbutton switch 3 serves for switching on and p the switch 4 for switchingoff th-e motor 1.

The motor drives, through an electromagnetically koperated plate clutch6, a shaft 37 and al pinion 3S, the

diagrammatioally indicated work carrier 7 ofthemachine and guides itback into the starting position shown in broken lines. For the purposeof operating the clutch 6, there are a push-button switch 9, y.aneng-aging relay 8, a transformer 1li, and a rectifier 11. Anelectromagnet 12, which is switched on when the relay is closed, isfalso connected to the engaging relay 8. The armature of this magnet isin operative connection, through a rod system (not shown), with a rod2l) in such manner that when the magnet 12 is switched on the rod 20 isso connected, through a locking rod system consisting of a `two-armedlever 31, 32 rockably mounted locks the feed device in the advancedposition, that when the magnet 12 is switched on the locking iscancelled.

A limit switch 13 is provided at the end of the return travel of thefeed means, which switch 13 is connected tothe `circuit breaker S andalso to a magnet 14 controlling the tool movement andthe work feedmovement. This magnet 14 is operatively connected to a rod whichtransmits the movement to operate a second switch-off magnet 17. To therod there are connected two switches 15 and 18 in such a manner that theswitch 15 when the rod is in disengaged position is inthe switchonposition and at the same time the switch 18 is held in switch-offposition, whereas when the rod is in engagement the switchl 15'is heldin switch-off position and the switch 18 in switch-on position. ITheswitch 15 lies in ythree-armed lever receives an oscillating movementfrom 'a cam 22 which makes one rotation with the shaft 29 during lthepunching of each groove. The arm 26 of the three-armed lever carries aroller 27 engaging the periph-ery of the cam 22. This cam 22 is alsoprovided in one side'face with a cam groove 23 controlling a switch 21in such a manner lthat the switch is held closed during the angle`ofrotation determined by the groove tem of a circuit breaker actuatedby the switoh-onpressf button switch, said circuit breaker controllingthe fast return travel coupling, for example, by means of a transformerfeeding t-he coupling actuating the electromagnet througha rectifier,and a magnetic release means for a locking `device adapted to hold thework feed means in its working and end positions, the larrangement beingsuch that the circuit breaker receiv-esoperating voltage over a switchdependent onthe tool engaging and disengaging movements, which switch isclosed. when the drive` ofthe tool tand of the work feed means isdisengaged.rv

Further features will beapparent rfrom the following description inconjunction with 'the claims and thedrawing which illustratesdiagrammatically the control system faccordingto the present invention.v 'f In the system illustrated there is connected to a three- 23.l Therod 20 in operative connection with the magnet 12 also acts on the arm24 of the three-armed lever 24, 25 and 25, which is mounted to rock4about pivot 28. The arm 26 of the three-armed lever bears through theroller 27 against the periphery of the cam disc 22, Which turns oncewith the crankshaft driving the ram 39 during-.the kstamping-out of aslot and imparts a pendulum movement to the three-armed lever24, 25 and26. On

the crankshaft 29 a crankdisc 40 is fastened, by which a lp-awl ratchetmechanism 41 is driven for the stepwise advance of the guide frame 7.

The operation ofthe saidV system is as follows:

In the villustrated position of the parts, the work feed means is in itsforemost position in which the guide frame 7 of the feed means holds thelimit switch 16 closed. 'Ihe rod for actuating the work feed and thetool move- Patented'Jan. 15, 1.957

The rodl 3 ment is in disengaged position, so that upon the closing ofthe switch 1S the circuit breaker 8 is pre-set for actuation. Before theswitch-on switch 9 is closed, the motor 1 is switched on by the pressbutton 3 over the circuit break-y er 2, which is Yshown in switch-ctiposition. The motor movement is`at .first not transmitted furtherbecausefthe,4 disc coupling 6 -is open. `By closing the `switch 9 theyelectromagnet which energizes 'the-disc coupling over y end of the lfastreturn stroke, the frame 7 actuates the limit switch 13 whereby thecircuit breaker 8 is de-energized and returns into `its switch-off`position so that the coupling 6 is again de-energized. The limit switch13 also energizes the engaging magnet 14 so thatY now the stepwiseoperating work feed and tool movement are initiated. At the beginning ofthe work stroke the switch 13, for example by the ,action of a springnot shown, returns to the illustrated position in which the closing ofthe circuit breaker 8 again becomes-possible. When mechanism afterinsertion of a `blank workpiece, and means operative for automaticallyswitching-on the high speed return and then switching-off the high speedreturn on reaching the end position, automatically switching-on thedrive for a tool and, dependently thereon, the intermittent workingfeed.

2. An electrical control Aarrangernent according to claim l, wherein anelectric motor is provided for the power I drive for the high speedreturn and adapted to be coupled such closing takes place, `the switch15 is opened, and

the switch 18 closed. The closing of the switch 18 prepares for theactuation of the disengaging magnet` 17. This takes place when the frame7 at .the end of its work stroke again closes the limit switch 16, orwhen the switch 21 .inparallelvwith the switch 16 is closed by theaction of the cam groove 23, as long as the rod 20 occupies a positionin which the switch 19 also `is`closed.

This is the case when the locking means forthe feed means, which isactuated by the rod 2G and, forexample,

may consist of a holder pin, has nct `arrived in the loclr- Y.

ing position.` The cam groove 23 `holds theiswitch 21 closed for a timecorresponding tothe period cf locking; on unlocking, the rod 20 isshifted in the direction'V end of this punch feed, the cam disc 22 isagain in the angular position which permits the' retraction of the rod l20 and simultaneous engagement of the locking means. Should the lockingmeans fail to operate so that the rod 20 does not return, then theswitch 19 would still be` closed and the switch 21 would be closed byvthe 4cam groove 23, and thereby the disengaging magnet 17 energized. Theparts 19and 21 to 2S thus constitute a safety device preventingoperation of the punching when the feed means is not locked.

The magnet 17 when itfis energized by the lim-it switch A 16 .or overthesafety switch 19, disengages the feed means i and the tool movement. Ifthe disengaging magnet is energized by the limit switch 16, then theparts, after the disengagement, are returned to the illustratedposition, except for the still running motor 1. After insertion of `anew blank in the guide frame, closing the switch 9 will initiate a newwork operation inthe manner hereinbefore described.

I claim: l, l. An electrical control `arrangement for a `slotting or`the like machine of the kind in which a worl: carrier or feed mechanismtherefor `is moved back to a starting position afterrthe completion of apre-determined numberof intermittent slotting `or punching workoperations, comprising a push button switch for switching-on a pc-werdriven high speed return of the work carrier :or feed and uncoupledthrough a plate clutch operated electroi magnetically in dependence onthe control arrangement, said motor being adapted to be switched on andott` through a relay operated by independent switching-on andswitching-olf buttons.

3. An electrical control arrangement according to claim l, wherein anelectric motor is provided for the power drive for thehigh speed returnand adapted to be coupled and uncoupled through a plate clutch operatedelectromagnetically in dependence on the control arrangement, said motorbeing adapted to be switched on and ofi through` a relay operated byindependent switching-on and switching-off b-uttons, and in which-aswitch relay is provided operated bythe engaging switch and by means ofwhich the high speed return `clutch is controlled feeding the clutchmagnet withxt-he aid of a rectifier, and in which aA magnetic releasedevice is provided for a locking means holding the feed device in theworking and end positions, while `the working voltage is supplied to theswitch relay through a switch dependent on the engagement anddisengagement ofthe tool, said last-mentioned switch being closed whenthe drive of the tool and ofthe working feed is disconnected.

4. A-n electrical control arrangement according to claim 1, wherein anelectric motor is provided for the power drive for the high speed returnand adapted to be coupled and uncoupled through a plate clutch operatedelectromagnetically in dependence on the` control arrangement, saidmotor being adapted to be switched on and ot through a relay operated byindependent switching-on and switching-off buttons, and in which aswitch relay is provided operated by the engaging switch and by means ofwhich the high speed return clutch is controlled feeding the clutchmagnet with the Vaid of a rectifier, and in which a magnetic releasedevice is provided for a locking means holding the feed device in theworking and end positionsfwhile lthe working voltage is supplied to theswitch relay througha switch dependent on the engagement anddisengagement of the tool, said last-mentioned switch being closed whenthe drive of the tool and of the Working feed is disconnected and asecond switch provideddependent on the engagement and disengagement ofthe tool including the switch by which the engaging relay is `connectedto voltage when disengagement occurs, said additional switch beingclosed in the engaged posi- `tion and is in the circuit of adisconnecting magnet so that the latter becomes operative as soon asfurther switches inthe same circuit are closed including a switchautomatically closed by the `feed* device at the end of the workcycle.

5. `fnzcelectrical control arrangement according to claim 1, whereinan'electric motor is provided for the power drive for the high speedreturn and adapted to be coupled and uncoupled` through a plate clutchoperated electromagnetically in dependence on the control arrangement,saidmotor being adapted to be switched on and off through a relayoperated by independent switching-on and switching-olf buttons, and inwhich a switch `relay is provided operated by the engaging switch and bymeans of which `the high speed return clutch is. controlled `feeding thec lutch magnet'withthe' aid of a rectifier, and in which a magneticrelease deviceis provided for a lock ing means holding the feed devicein the working and end positions, while the working voltage is suppliedto the switch relay through a switch dependent on the engagevment anddisengagement of the tool, said last-mentioned switch being closed whenthe drive of the tool iand of 'che References Cited in the le of thispatent working feed is disconnected, and a switch operated by UNITEDSTATES PATENTS the feed device at the end of lthe high speed return of 1257 507 Malocsay Feb' 26 1918 the latter provided for a magnet effectingthe engagement 638:662 Rothwell May 19 1953 of the tool and working feeddrive `and at the same time 5 releases the engaging relay.

